Hello -- and you are not alone! I was glad to see your post/question. We administratively did the same thing, based on whether the plan allowed all sources or limited sources. I asked the same question at an FIS Advanced Pension Conference and was told (I believe by Derrin Watson) that we couldn't have two defaults signed by us as the document sponsor. We need to "pick one" as our default and sign the amendment on the plan's behalf. For the second group, the employer needs to sign the amendment. Obviously, we are not excited about that answer! I'm interested in your "if this, then this" words approach in the amendment as an alternative, and I'm curious to see if others are in the same boat...